268 FF. Galton—Address before the British Association. 
imagine few greater services to anthropology than the collec- 
tion of the various experiments that have been imagined to re- 
duce the faculties of the mind to exact. measurement. ey 
have engaged the attention of the highest philosophers, but 
have never, so far as I am aware, been brought .compendiously 
together, and have certainly not been introduced, as they de- 
serve, to general notice. 
Wherever we are able to perceive differences by inter-com- 
arison, we may reasonably hope that we may at some future 
The history of science is the history of such triumphs. I will 
ask your attention to a very notable instance of this, namely, 
that of the establishment of the scale of the thermometer. You 
are aware that the possibility of making a standard thermomet- 
ric scale wholly depends upon that of determining two fixe 
points of temperature, the interval between them being gradu- 
ated into a seale of equal parts. These points are, I nee 
hardly say, the temperatures of freezing and of boiling water 
respectively. On this basis we are able to record temperature 
with minute accuracy, and the power of doing so has been one 
of the most important aids to physics and chemistry as well as 
to other branches of investigation. We have been so accus- 
tomed, from our childhood, to hear of degrees of temperature, 
and our scientific knowledge is so largely based upon exac 
thermometric measurement, that we cannot easily realize the 
state of science when the thermometer, as we now use it, was 
unknown. Yet such was the condition of affairs so recently as 
two hundred years ago, or thereabouts. The invention of the 
thermometer, in its present complete form, was largely due to 
Boyle, and I find in his “ Memoirs” (London, 1772, vol. vi, P» 
403), a letter that cannot fail to interest us, since it well ex- 
presses the need of exact measurement that was then felt in 4 
particular case, where it was soon eminently well supplied, and 
therefore encourages hope that our present needs as anthropol- 
ogists may hereafter, in some way or other, be equally well sat- 
isfied. - The letter is from Dr. John Beale, a great friend and 
correspondent of Boyle, and is dated February, 1663. He 
says in 1t:— 
“T see by several of my own thermometers that the glass- 
men are by you so well instructed to make the stems in equa 
proportions, that if we could name some degrees, .. + - 
might by the proportions of the glass make our discourses intel- 
ligible in mentioning what degrees of cold our greatest frosts 
do produce. .... If we can discourse of heat and cold im 
their several degrees, so as we may signify the same intelligi 
y, .... itis more than our forefathers have taught us to do 
hitherto.” 
